Figure 3-23.The parts of a piston.examples of conditions that a piston must withstand atThe piston head is subjected to temperatures wellnormal highway speed:above 600°F.As the piston moves from the top of the cylinderThe structural components of the pistons are theto the bottom (or vice versa), it accelerates from aHEAD, SKIRT, RING GROOVES, and LANDS (fig.stop to a speed approximately 50 mph at3-23); however, all pistons do not look like the typicalmidpoint, and then decelerates to a stop again. Itone shown here. Some have differently shaped heads.does this approximately 80 times per second.Diesel engine pistons usually have more ring groovesand rings than the pistons of a gasoline engine. Some ofThe piston is subjected to pressures on its head inthese rings may be installed below as well as above theexcess of 1,000 psi.WRIST or PISTON PIN (fig. 3-24).Figure 3-24.Diesel piston assembly.3-16